This is the 9802nd most frequent Catalan word.
mencionen
"Menionen" means "they mention."
The word 'mencionen' in this sentence is used as a verb in the third person plural form to indicate that the subject (the students) is performing the action of mentioning.
Els estudiants mencionen els noms dels seus professors.
The students mention the names of their teachers.
Here, 'mencionen' is again a verb in the third person plural. It is used as a reporting verb to introduce a statement or fact discussed by the subject in conversation.
Mencionen que aquest llibre és molt útil.
They mention that this book is very useful.
In this case, 'mencionen' is used in an interrogative form to question the habitual action of mentioning carried out by the subject.